What I've observed is that Parallels has always been able to make its upgrades compelling. In part, that's because there is so much to do and there are so many opportunities with this technology. Also, these guys are virtual machine experts and employ most of the world's talent with VMs. Another contributor is that customers who press various virtual machines into service on their Macs do so much and encounter so many scenarios that they can provide plentiful feedback on what they want in the next version. Parallels then just does it.

The Review

As with OS X, there is a list of features created by the developer, and then there are notable features that are compelling and destined to be a signature feature of a release.

It makes sense to list all the new features of Parallels Desktop 10 (PD10) for the record, but later in this review I'll focus on those things that stood out for me and could also be readily tested in Mavericks.

Features of Interest for the everyday user are listed here. There are also some new features for developers, designers and IT pros that I'll leave to the official press release.The wording of the next three sections is from Parallels.

Performance and Optimization

Users can now open Windows documents up to 48 percent faster

Battery life is extended by up to 30 percent giving people additional work time when they need it most

Virtual machine only takes as much disk space on the Mac hard drive as it needs. Real- time optimization automatically compacts virtual disk eliminating the need for periodic manual compacts.

Free Disk Space Wizard allows to review and clean up space used by Parallels Desktop and Virtual Machines

Easy to Get Started

Now with one click users can select from a number of choices to optimize their virtual machine based on what their primary usage is: productivity, games, design or development

The new Parallels Control Center is a one-stop-shop for managing Parallels Desktop; it allows users to manage all their virtual machines and configuration settings from a single place

Windows installation has been streamlined, with new ways to configure virtual machines

Regional settings from the Mac are now set by default in Windows virtual machines

Seamless Integration for Best User Experience

Users can share files, text or web pages from Windows using Internet accounts configured on their Mac such as Twitter, Facebook, Vimeo, Flickr; or send them via email, AirDrop and Messages.

When users install a new Windows application, its icon will automatically be added to the OS X Launchpad

The unread email indicator on Outlook lets users see at a glance the number of unread emails in Outlook, just like with Apple Mail

Users can drag and drop files to the virtual machine icon in the Dock to open in Windows

Users also have the ability to easily restore any setting to its default value by clicking the Restore Defaults button in the Virtual Machine Configuration window

Users can drag and drop files to Mac OS X virtual machines

Next: Favorite New Features.

Page 2 - My Favorite New Features

So much for the list from Parallels. All of the new features are great, but here are my favorites, from #1 down to #6. I tested them all and took screen shots.

1. Control Panel. The list of available VMs is maintained in a beautiful and functional Control Panel. Not only are the tiles active, as before, but there are expanded options right next to the tiles for Settings, the location of the VM, and the status of antivirus protection. Notice how in the screen shot below, the disk icon indicates that my VMs are stored on an external drive. That's so they don't take up precious space on my meager, internal 256 GB SSD.

The ability to start, configure and see VM location is right there.

2. Disk Space Management. As mentioned in the original product news article, Parallels has paid special attention to MacBook Air/Pro owners who are transitioning from hard disks to SSD or Flash storage and may have less storage than they had with a hard disk. That means making sure that the snapshots and VM disk space aren't using more storage than absolutely. necessary. To that end, there is a Disk Space Wizard that surfaces usage and allows the user to recover space. This is vital for MacBook Airs with 128 GB of Flash and helpful with 256 GB.

Ways to save on space surfaced to user.

3. Installing a virtual machine has always been easy. You'd just navigate to the ISO file and be on your way. PD10 makes it even easier: just drag the ISO file to the PD10 app icon and it's recognized as an installable OS. PD10 knows how to send to the guest OS installer those things it wil need, for example, the administrator's name and password. Then, you're stepped through other details with a beautiful GUI and you get to see the progress until the VM is ready to launch.

Drag ISO image file to Parallels app and start filling in some forms. On your way.

Next: More Favorite Features

Page 3 - More Favorite Features

4. Drag file to Windows app in Dock. Once nice feature of PD10 is that not only can you have one of the apps of Windows in the OS X dock, but you can drag a compatible file to that icon. The VM will launch, then the VM's app will launch and load the file you dragged. This is just one of the incremental steps that makes Parallels so easy to use.

5. Launchpad refinements. Regardless of how popular Launchpad may be, is a good place to setup a visual connection between the VMs and a Mac. In PD10, when you install a new Windows app, it's icon is added to launchpad for easy access. I have read that Switchers, in love with their new Macs, but still using Windows, like this.

These folders are created automatically.

6. More performance. There are now called Optimal Settings (Windows only). This is different than Settings > Options > Optimization where you can chose between a faster virtual machine or a faster Mac. Optimal Settings, set either during installation or after the fact can manage how you plan to use Windows.

More performance by specifying usage profile.

Yosemite Support

Parallels Desktop 10 introduces some Yosemite specific features. I did not test these because of the configuration and state of my various Macs, so I'll just list them for the record.

iCloud Drive support from Windows.

iMessage/SMS text sharing from Windows.

Yosemite look and feel followed.

Notification Center Integration.

Next: Windows Purchasing, Antivirus, FInal Words

Page 4 - Windows Purchasing, Antivirus, FInal Words

Windows Purchasing Issue

In the past, Parallels customers had the opportunity to purchase a fully licensed Windows within the installer. This version doesn't have that option. Parallels told me:

We are working with Microsoft to give Parallels Desktop users an elegant way to purchase and install Windows. Unfortunately, these negotiations are still on-going. For users of Parallels Desktop who are developers (either app developers or web developers), there are 90-day trials of many different versions of Windows available for free download. Click the following button to begin the selection of a 90-day trial:

90 day test versions odf Windows designed for developers.

Antivirus Software

The Parallels website says:

Parallels Desktop allows you to install the antivirus software powered by Kaspersky on your Mac and in Windows XP, Windows Vista, and Windows 7 virtual machines with Parallels Tools installed. This antivirus software is provided with a free activation key for 90 days. When the trial period expires, you can purchase a permanent activation key.

Final Words

I have been impressed with every upgrade from Parallels for this product. I think the features are compelling for an everyday user, and well worth the $50 upgrade price. However, for casual users who only fire up Windows every few months, an upgrade may not be critical—but I wouldn't think of skipping two upgrade cycles. Not only are new features added, but the interface is smoother, and Parallels extracts every ounce of performance possible to make using a VM transparent and easier to use.

If you're interested in detailed benchmarks, Jim Tanous over at TekRevue has posted them for this version. While computational performance hasn't changed, there is some quantifiable improvement in (MacBook) battery life VM launch times. Whether those minor improvements matter depends on your Mac's capabilities and your daily usage.

Finally, an issue has come up regarding the ability to run Parallels 9 with the latest betas of Yosemite, and that relates. I surmise, to the problems any developer has with code that changes from beta to beta release. TekRevue discusses that issue as well, and it's something to be aware of if you plan to upgrade to Yosemite but not to PD10. The situation seems to be in flux.

Parallels Desktop 10 is priced at US$79.99 and there is student pricing at $39.99. Current users can upgrade for $49.99.

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Reviewer's note: A Microsoft spokesperson declined to provide a copy of Windows 8.1 for testing with PD10.